1. Field of the invention
The present invention concerns devices generally employed to hold onto the worktable of a machine tool workpieces to be machined on it.
2. Description of the Prior Art
These clamping devices are usually in the form of a casing which is fixed to a worktable by means of an assembly member cooperating with a block sliding in a groove in the worktable and inside which is a mobile part rotatable about a horizontal axis which has a toothed sector cooperating with a lead screw, said mobile part incorporating an arm forming a lever the end of which bears on the workpiece to be machined.
In known clamping devices the aforementioned arm is attached to the mobile part, which rules out any possibility of adjusting its position relative to the casing.
What is more, in some applications it may be useful to provide an upward clamping or supporting action, by raising the lever arm.